${8 \div 0.4 = {?}}$
Answer: $ {8 \div 0.4 = 8 \div \dfrac{4}{10}} $ $ {\phantom{8 \div 0.4} = 8 \div \dfrac{2}{5}} $ Dividing by a fraction is the same as multiplying by the reciprocal of the fraction. $ {8 \div \dfrac{2}{5} = 8 \times \dfrac{5}{2}} $ $ {\phantom{8 \div \dfrac{2}{5}} = \dfrac{8 \times 5}{2}} $ $ {\phantom{8 \div \dfrac{2}{5}} = \dfrac{40}{2}} $ $ {\phantom{8 \div \dfrac{2}{5}} = 20} $